Last year I bought a used generator and posted a thread requesting help to determine the best way to wire the generator into the house load and into the air conditioners. My boat is a Morgan 415 Out Island and utilizes two 30 amp shore power cords. One cord is dedicated to the house load and the other to two air conditioners. The generator is a 7.5kw (over kill I know) and has just two lines coming out (hot and neutral with ground being the generator casing). In response to my original thread, Stu Jackson was kind enough to provide a design utilizing a generator transfer switch (see attachment). Now that my back is mended (4 vertebrae fused), I am anxious to get started wiring. When buying supplies I was shocked to learn how expensive a 60 amp transfer switch is (~400$)!
For the sake of economy, I was wondering if it would be prudent to use a pair of 3PDT 40 amp power relays that I have. Using Stu’s wiring diagram as an aide, I came up with a design (see attachment). However, I am beginning to wonder if using relays is such a smart idea. Specifically, I am concerned about the case of one relay making contact to the generator while the other is connected to shore power. In an attempt to minimize harm (perhaps in my fantasies) I use one relay to switch the two black shore leads simultaneously. However, I suspect this is still not adequate. I wonder what the good folk at ABYC would have to say about using relays.
I appeal to the collective knowledge of the sailors here to help design a safe (and hopefully economical) solution for wiring up my generator.
Note: My preliminary design does not show the circuitry that energizes the relays. Also, in my diagram, I show the relays not making contact. If using the relays in lieu of a transfer switch, I would be sure that the relays, when not energized, connect with shore power.
For the sake of economy, I was wondering if it would be prudent to use a pair of 3PDT 40 amp power relays that I have. Using Stu’s wiring diagram as an aide, I came up with a design (see attachment). However, I am beginning to wonder if using relays is such a smart idea. Specifically, I am concerned about the case of one relay making contact to the generator while the other is connected to shore power. In an attempt to minimize harm (perhaps in my fantasies) I use one relay to switch the two black shore leads simultaneously. However, I suspect this is still not adequate. I wonder what the good folk at ABYC would have to say about using relays.
I appeal to the collective knowledge of the sailors here to help design a safe (and hopefully economical) solution for wiring up my generator.
Note: My preliminary design does not show the circuitry that energizes the relays. Also, in my diagram, I show the relays not making contact. If using the relays in lieu of a transfer switch, I would be sure that the relays, when not energized, connect with shore power.
